1. Field of the Invention
One or more embodiments of the present invention relate to a method of manufacturing a thin film transistor (TFT) substrate and a method of manufacturing an organic light emitting display apparatus.
2. Description of the Related Art
In general, a thin film transistor (TFT) substrate is a substrate on which TFTs are formed. In addition to the TFTs, a TFT substrate may further include components such as capacitors.
FIG. 1 is a schematic cross-sectional diagram of a TFT substrate manufactured according to a conventional TFT substrate manufacturing method.
Referring to FIG. 1, a TFT 20 and a capacitor 30 are formed on a substrate 10. A first capacitor electrode 31 of the capacitor 30 and a semiconductor layer 23 of the TFT 20 are formed in a same layer, a second capacitor electrode 32 of the capacitor 30 and a gate electrode 25 of the TFT 20 are formed in a same layer, and a gate insulating layer 11 is formed between the first and second capacitor electrodes 31 and 32 and between the semiconductor layer 23 and the gate electrode 25. An interlayer insulating layer 13 is formed on the second capacitor electrode 32 and the gate electrode 25, and source and drain electrodes 21 and 22 are formed on the interlayer insulating layer 13.
If an organic light emitting display apparatus is manufactured by using the TFT substrate illustrated in FIG. 1, since the first capacitor electrode 31 and the semiconductor layer 23 may be formed in the same layer by using the same material and the second capacitor electrode 32 and the gate electrode 25 may be formed in the same layer by using the same material, in order to obtain a voltage range sufficient to operate the capacitor 30, a circuit modification is required by, for example, connecting wires for applying electrical signals to the first and second capacitor electrodes 31 and 32 from a new wire (e.g., an electrode power supply line) instead of a conventional wire (e.g., a power supply line) of the organic light emitting display apparatus. Accordingly, defects may occur.